diff --git a/gba_memory.c b/gba_memory.c
index d966a46..0099b98 100644
--- a/gba_memory.c
+++ b/gba_memory.c
@@ -2447,7 +2447,19 @@ bool gamepak_must_swap(void)
 
 void init_memory(void)
 {
-  u32 map_offset = 0;
+  u32 map_offset = 0, i;
+
+  for (i = 0; i < DMA_CHAN_CNT; i++)
+  {
+    dma[i].start_type = DMA_INACTIVE;
+    dma[i].irq = DMA_NO_IRQ;
+    dma[i].source_address = dma[i].dest_address = 0;
+    dma[i].source_direction = dma[i].dest_direction = 0;
+    dma[i].length = 0;
+    dma[i].length_type = DMA_16BIT;
+    dma[i].repeat_type = DMA_NO_REPEAT;
+    dma[i].direct_sound_channel = DMA_NO_DIRECT_SOUND;
+  }
 
   // Fill memory map regions, areas marked as NULL must be checked directly
   map_region(read, 0x0000000, 0x1000000, 1, bios_rom);
diff --git a/libretro/libretro.c b/libretro/libretro.c
index 44b6443..1135d24 100644
--- a/libretro/libretro.c
+++ b/libretro/libretro.c
@@ -566,7 +566,7 @@ void retro_init(void)
 #endif
 
    init_gamepak_buffer();
-   init_sound(1);
+   init_sound();
 
    if(!gba_screen_pixels)
 #ifdef _3DS
diff --git a/main.c b/main.c
index a162d98..fb4dc89 100644
--- a/main.c
+++ b/main.c
@@ -82,13 +82,14 @@ static unsigned update_timers(irq_type *irq_raised, unsigned completed_cycles)
 void init_main(void)
 {
   u32 i;
-
   for(i = 0; i < 4; i++)
   {
-    dma[i].start_type = DMA_INACTIVE;
-    dma[i].direct_sound_channel = DMA_NO_DIRECT_SOUND;
     timer[i].status = TIMER_INACTIVE;
-    timer[i].reload = 0x10000;
+    timer[i].prescale = 0;
+    timer[i].irq = 0;
+    timer[i].reload = timer[i].count = 0x10000;
+    timer[i].direct_sound_channels = TIMER_DS_CHANNEL_NONE;
+    timer[i].frequency_step = 0;
   }
 
   timer[0].direct_sound_channels = TIMER_DS_CHANNEL_BOTH;
diff --git a/sound.c b/sound.c
index 0ad5d6f..4e862db 100644
--- a/sound.c
+++ b/sound.c
@@ -549,6 +549,7 @@ void reset_sound(void)
     ds->fifo_top = 0;
     ds->fifo_base = 0;
     ds->fifo_fractional = 0;
+    ds->volume_halve = 1;
     memset(ds->fifo, 0, 32);
   }
 
@@ -561,6 +562,7 @@ void reset_sound(void)
   gbc_sound_master_volume = 0;
   memset(wave_samples, 0, 64);
 
+  memset(&gbc_sound_channel[0], 0, sizeof(gbc_sound_channel));
   for(i = 0; i < 4; i++, gs++)
   {
     gs->status = GBC_SOUND_INACTIVE;
@@ -569,7 +571,7 @@ void reset_sound(void)
   }
 }
 
-void init_sound(int need_reset)
+void init_sound()
 {
   gbc_sound_tick_step =
    float_to_fp16_16(256.0f / sound_frequency);
@@ -577,8 +579,7 @@ void init_sound(int need_reset)
   init_noise_table(noise_table15, 32767, 14);
   init_noise_table(noise_table7, 127, 6);
 
-  if (need_reset)
-    reset_sound();
+  reset_sound();
 }
 
 bool sound_read_savestate(const u8 *src)
@@ -633,7 +634,6 @@ bool sound_read_savestate(const u8 *src)
       bson_read_int32(sndchan, "env-vol", &gs->envelope_volume) &&
       bson_read_int32(sndchan, "env-dir", &gs->envelope_direction) &&
       bson_read_int32(sndchan, "env-status", &gs->envelope_status) &&
-      bson_read_int32(sndchan, "env-step", &gs->envelope_step) &&
       bson_read_int32(sndchan, "env-ticks0", &gs->envelope_initial_ticks) &&
       bson_read_int32(sndchan, "env-ticks", &gs->envelope_ticks) &&
       bson_read_int32(sndchan, "sweep-status", &gs->sweep_status) &&
@@ -705,7 +705,6 @@ unsigned sound_write_savestate(u8 *dst)
     bson_write_int32(dst, "env-vol", gs->envelope_volume);
     bson_write_int32(dst, "env-dir", gs->envelope_direction);
     bson_write_int32(dst, "env-status", gs->envelope_status);
-    bson_write_int32(dst, "env-step", gs->envelope_step);
     bson_write_int32(dst, "env-ticks0", gs->envelope_initial_ticks);
     bson_write_int32(dst, "env-ticks", gs->envelope_ticks);
     bson_write_int32(dst, "sweep-status", gs->sweep_status);
@@ -721,6 +720,9 @@ unsigned sound_write_savestate(u8 *dst)
     bson_write_int32(dst, "len-ticks", gs->length_ticks);
     bson_write_int32(dst, "noise-type", gs->noise_type);
     bson_write_int32(dst, "sample-tbl", gs->sample_table_idx);
+
+    // No longer used fields, keep for backwards compatibility.
+    bson_write_int32(dst, "env-step", 0);
     bson_finish_document(dst, wbptr2);
   }
 
diff --git a/sound.h b/sound.h
index ac84bda..2f660a2 100644
--- a/sound.h
+++ b/sound.h
@@ -66,7 +66,6 @@ typedef struct
    u32 envelope_volume;
    u32 envelope_direction;
    u32 envelope_status;
-   u32 envelope_step;
    u32 envelope_ticks;
    u32 envelope_initial_ticks;
    u32 sweep_status;
@@ -102,7 +101,7 @@ void sound_timer_queue32(u32 channel, u32 value);
 unsigned sound_timer(fixed8_24 frequency_step, u32 channel);
 void sound_reset_fifo(u32 channel);
 void update_gbc_sound(u32 cpu_ticks);
-void init_sound(int need_reset);
+void init_sound();
 unsigned sound_write_savestate(u8 *dst);
 bool sound_read_savestate(const u8 *src);